The buckets of mechanical shovels are provided at their base with a strip upon which teeth are fixed. As these teeth can wear out fairly quickly when moving earth in hard ground, they often have to be replaced, and the worn out teeth are thrown away even though they still constitute a large mass of special steel which is thus lost.
In order to avoid these losses, it has been proposed that each tooth be made in two parts, namely a first part forming a support fixed to the blade and ending in a nose, and a second, wearing part, in the form of a hollow tooth which is replaceably mounted on the nose. In use, the hollow tooth is replaced when it wears out, but the support part, which contains the larger weight of metal, is retained.
The hollow tooth is fixed to the supporting nose by a system of cotters. In particular, a known method involves making a substantially vertical hole in the nose and the tooth and inserting in the hole a steel cotter connected to a rubber block which keeps the cotter in place. However, this system is not entirely satisfactory and teeth frequently become detached from their support.